From: Nathan Lynch Date: Sun, 28 Sep 2014 23:50:06 +0000 (+0200) Subject: clocksource: arm_arch_timer: Change clocksource name if CP15 unavailable X-Git-Tag: firefly_0821_release~176^2~3104^2~3 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=423bd69e69f565167ba14e2fe61df76c3c4a0d26;p=firefly-linux-kernel-4.4.55.git clocksource: arm_arch_timer: Change clocksource name if CP15 unavailable The arm and arm64 VDSOs need CP15 access to the architected counter. If this is unavailable (which is allowed by ARM v7), indicate this by changing the clocksource name to "arch_mem_counter" before registering the clocksource. Suggested by Stephen Boyd. Signed-off-by: Nathan Lynch Reviewed-by: Stephen Boyd Signed-off-by: Daniel Lezcano Acked-by: Will Deacon --- diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 7e267e3990ab..e0e7729d37fd 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -429,11 +429,19 @@ static void __init arch_counter_register(unsigned type) u64 start_count; /* Register the CP15 based counter if we have one */ - if (type & ARCH_CP15_TIMER) + if (type & ARCH_CP15_TIMER) { arch_timer_read_counter = arch_counter_get_cntvct; - else + } else { arch_timer_read_counter = arch_counter_get_cntvct_mem; + /* If the clocksource name is "arch_sys_counter" the + * VDSO will attempt to read the CP15-based counter. + * Ensure this does not happen when CP15-based + * counter is not available. + */ + clocksource_counter.name = "arch_mem_counter"; + } + start_count = arch_timer_read_counter(); clocksource_register_hz(&clocksource_counter, arch_timer_rate); cyclecounter.mult = clocksource_counter.mult;